1. Field of the Invention
The present invention relates to a magnetic sensor device which converts a magnetic field intensity to an electric signal, and to a magnetic sensor device capable of attaining low power consumption while improving the accuracy of detecting a magnetic field.
2. Background Art
FIG. 7 is a circuit diagram of a related art magnetic sensor device. The related art magnetic sensor device is equipped with a magnetic sensor circuit 710, a CLK circuit 108, an ONOFF control circuit 730, and an output terminal 103. The magnetic sensor circuit 710 is equipped with a sensor element 104, a differential amplifier circuit 105, a comparison circuit 106, a latch circuit 704, and an NMOS transistor 705.
FIG. 8 is a timing chart illustrating the operation of the related art magnetic sensor device. The CLK circuit 108 outputs a clock signal of such a certain cycle Tclk as illustrated in FIG. 8. The ONOFF control circuit 730 generates a control signal having a cycle Tcycle from the clock signal and outputs it therefrom. The magnetic sensor circuit 710 performs an intermittent operation in a timing at which the control signal becomes H to realize low current consumption.
The sensor element 104 outputs a Hall voltage according to a magnetic field or a magnetic flux density. The differential amplifier circuit 105 amplifies the Hall voltage, and the comparison circuit 106 outputs a detection/non-detection signal by comparing the Hall voltage and a certain voltage. The latch circuit 704 holds the detection/non-detection signal even during an off period of the intermittent operation. The NMOS transistor 705 is controlled in on/off by the output signal of the latch circuit 704, which is inputted to a gate thereof. The output terminal 103 is connected with a pull-up resistor to thereby output an H/L signal corresponding to the presence or absence of the magnetic field or magnetic flux density, whereby the magnetic sensor circuit 710 of low current consumption is realized (refer to, for example, Patent Document 1, FIG. 2).
[Patent Document 1] Japanese Patent Application Laid-Open No. 2006-153699